Lithium ion battery technology is becoming the standard for rechargeable energy storage systems. Lithium ion batteries are able to store up to three to four times as much electric energy as currently used rechargeable batteries.
However, current lithium ion battery pack balancing technology has the disadvantage that it requires complex and costly electronic control and balancing circuitry that may be inactive for long periods of time.
Accordingly, there exists a need for a battery pack control module which can continuously balance cells using continuously active control circuits.
Currently, balancing the capacities of series connected lithium ion cells in a battery pack system is accomplished using resistors connected by switches across each cell combined with cell voltage monitoring and computer control. The resistors dissipate a relatively small amount of power and are activated infrequently. Large battery packs with multiple sources of differential leakage currents cause the battery pack capacity to diminish and not be available for rapid use at all times.
A need exists for a battery pack control module to continuously minimize the loss of capacity that occurs in large lithium ion battery pack systems.
The present embodiments address these needs.